1. Field of the Invention
The present invention relates to an image forming apparatus which corrects a condition of transfer and an image forming system which includes this image forming apparatus.
2. Description of Related Art
In a process of printing performed by an ordinary image forming apparatus such as an apparatus with an electrophotographic method, first of all, a surface of a holder of an image is uniformly charged. On this surface of a holder of an image, a prescribed electrostatic latent image is formed by exposing the surface to a light. The electrostatic latent image is developed by a toner. Then, an image is formed with toner on the surface of a holder of the image. This image of toner is transferred, based on a control of levelling voltage or levelling current, on a recording medium by a transferring unit. A feature of the transfer is much influenced by a change of temperature or humidity of circumstances. To decrease this influence to be as low as possible, a method for controlling transfer is disclosed. This method is a method for transferring with a condition. This condition is set based on a resistance of the transferring unit. This resistance is calculated from a current detected and a voltage generated, when a prescribed current is flown in the transferring unit (c.f. JP2001-83751). Moreover, another method for controlling transfer is disclosed. This method is a method for transferring with a condition. This condition is set based on data obtained from a thermal sensor (c.f. JP11-305565).
Even in case that the two methods mentioned above are used, all the users cannot always obtain the best result of printing which they want.
In case that either of the two methods mentioned above are used, each user can obtain near to the best result of printing which he or she wants. However, following inconvenience occurs. It occurs when an image forming apparatus is connected to a network and the image forming apparatus is commonly used by many users. When one of the many users changed the condition of transfer according to his own choice, other users do not like the changed condition. Then, another user obtains a result of printing which he does not want.
That is, there is a problem to solve, that either of the other users obtain a result of printing which he does not want, when an image forming apparatus is connected to a network and the image forming apparatus is commonly used by many users, in case that one of the many users changed the condition of transfer according to his own choice and other users do not like the changed condition.